The present invention relates to a radiating cable for use in particular in the field of cellular telephony or in local area networks for transmitting data by wireless at up to about 2.4 gigahertz (GHz).
The provision of radio coverage in large buildings often requires dedicated equipment to be installed. This coverage is obtained by means of antennas placed inside such buildings.
Technically, it would be advantageous to use radiating cables based in passages, however that gives rise to costs that are often unacceptable. Present-day radiating cables are coaxial cables with slots in periodic patterns and they are expensive, bulky, rigid, and difficult to lay.
Furthermore, when cabling buildings, the high levels of performance provided by present-day radiating cables are unnecessary. The object of the invention is to propose a radiating cable of low cost that is easy to lay, while presenting performance that is sufficient to ensure satisfactory transmission of signals within a building or a vehicle.
The present invention provides a radiating cable comprising a pair of insulated conductor wires, at least one cable segment having first ends connected to a load equal to a characteristic impedance of the cable segment, and second ends connected to a connector. This provides a cable of very great flexibility and compactness which can easily be fixed in the passages of a building by means of the usual techniques for fixing an ordinary telephone cable and which also presents impedance that is independent of length.
In an advantageous version of the invention, the cable has at least two cable segments whose second ends are connected in parallel to the connector. Given the equivalent impedance obtained by connecting the cable segments in parallel, this makes it possible to provide a cable that presents impedance matched to the transceiver to which the radiating cable is connected while making the radiating cable out of cable segments each presenting an impedance that is higher, i.e. generally having better transmission performance than a single cable matching the nominal impedance of the transceiver.
In yet another advantageous aspect of the invention, the two cable segments are identical. This minimizes constraints on storage, and the cable can be installed without any need to identify the cable segments.
Other characteristics and advantages of the invention will appear on reading the following description of a particular non-limiting embodiment of the radiating cable of the invention, given with reference to the accompanying figures, in which: